1. Field
Exemplary embodiments of the inventive concept relate to a light source device, a driving method of the light source device and a display device having the light source device. More particularly, exemplary embodiments of the inventive concept relate to a light source device capable of preventing luminance from being decreased, a driving method of the light source device and a display device having the light source device.
2. Description of the Related Art
Generally, liquid crystal display (“LCD”) devices have thinner thickness, lighter weight, and lower power consumption than other types of display devices. Thus, LCD devices are being widely used not only for monitors, notebook computers, and cellular phones, but also for wide-screen televisions. An LCD device includes an LCD panel displaying images using the light transmissivity property of a liquid crystal layer, and a backlight assembly providing the LCD panel with light.
The backlight assembly includes a light source that generates light. For example, the light source may be a cold cathode fluorescent lamp (“CCFL”) or a light-emitting diode (“LED”). The LED is used as a light source for an LCD panel, because the LED has low power consumption and high color reproducibility.
Plural LEDs are coupled in series to define an LED string, and the LEDs are emitted by a driving current according to a suitable driving voltage by a control of an LED driving circuit. When the driving voltage is greater than necessary, unnecessary power consumption is generated. When the driving voltage is excessively small, it is difficult to supply a stable current due to a forward voltage variation of each LED. Thus, an LED driving circuit which removes unnecessary power consumption and can supply a suitable current is required.
In order to supply a suitable current, the LED driving circuit adjusts an average current flows through the LED strings by adjusting a duty cycle of a transistor connected to end terminals of LED strings based on an LED current measured per LED strings. However, when the luminance variation of LED becomes great, the luminance of the LCD device decreases greatly.